Room air conditioner mixing fresh and recirculated air



Feb. 6, 1951 A. B. NEWTON 2,540,957

ROOM AIR CONDITIONER MIXING FRESH AND RECIRCULATED AIR Filed April 12, 1947 2 Sheets-Sheet 1 ooooooo'oooooo I INVENTOR. E-En gin/1 71 ,B. Nell/fail.

Feb. 6, 1951 A. B. NEWTON 2,540,957

ROOM AIR CONDITIONER MIXING FRESH AND RECIRCULATED AIR Filed April 12, 1947 2 Sheets-Sheet 2 OUfSI JB azr aufszile a1 palm-Zara: To oufaz'le.

I mw i I E3 L r INVENTOR.

B New/07!.

meme Feb. 11, 1951 i z 54 957 UNITED sin-es PATENT firms BOOM AIR CONDITIONER MIXING FEES AND RECIRCULATED AIR B. Newton, Dayton, Ohio, allignor to Chrysler Corporation, Highland Park, Mich, a corporation of Delaware Application April 12, 1947, Serial No. 741,082

Claims. (01. 62-129) This invention relates to apparatus adapted to utilize a multiple effect refrigeration system in a room air conditioner.

i It is an object of this invention to incorporate in a room air conditioner a refrigeration system having two cooling coils, one of which cools fresh incoming air and the other of which is maintained at a relatively lower temperature to cool recirculated room air. The latter coil, if desired may also additionally cool the fresh incoming air. Both of these coils are operatively associated with one compressor provided in the system.

It is a further object of the invention to provide in an airstream two cooling coils arranged in series and each adapted to discharge into one compressor. The upstream cooling coil discharges into the compressor cylinder at a location between the limits of piston travel. The downstream cooling coil discharges into the compressor through the usual suction valve located in the head of the compressor cylinder.

An additional object of the invention is to improve the efflciency of refrigeration apparatus used in a room air conditioner by utilizing a plurality of cooling cois each operating at its optimum pressure and temperature.

It is a further object of the invention to obtain a maximum dehumidification of air being cooled with a minimum of volume of refrigerant. It has been found by experience that dehumidification does not occur unless there is about a 30 temperature differential between the temperature of the refrigerant in the system and the temperature of air being cooled by the system. In an air conditioner where recirculated air is to be mixed with fresh incoming air if one cooling coil only is used to cool the mixture it is necessary that this coil operate inefliciently by handling an excessive volume of refrigerant if the 30 differential in temperature is to be obtained. If the fresh incoming air is cooled by one coil and the mixed fresh air and recirculated room air are cooled by another coil the 30 difl'erental may be obtained between each coil and its associated air with a maximum of efliciency.

that it may make a plurality of passes over the cooling coils before being discharged from the conditioner to the room.

A further object of the invention is to provide a unit capable of supplying correctly conditioned air in the amounts and in the direction desired by the occupants of a room. This includes means to treat fresh air and recirculate room air in the respective .quantities desired for proper ventilation of the room. This also includes means for controlling the direction of flow of air into the room from the unit and means for controlling the velocity thereof so as to prevent objection- I able drafts.

Means are also provided herein to permit fresh outside air to be mixed with room air being circulated through the conditioner and to provide a selection of precooled or preheated outside air or a combination of the two for this mixture.

In the drawings:

Fig. 1 is a plan view of the unit with the top removed,

Fig. 2 is a front elevation of the unit with parts thereof broken away to illustrate interior details,

Fig. 3 is a vertical section taken on the line 33 of Fig. 2,

Fig. 4 is a schematic drawing of the refrigeration system used in the unit,

Fig. 5 is a perspective view of a portion of the unit and has parts thereof broken away to illustrate details,

Fig. 6 is an enlarged view of the air discharge control means, and

Fig. 7 is a schematic diagram showing the paths offlair relative to the refrigeration system in the u A casing i0 houses the unit; The casing preferably is in the shape of an inverted L with the leg thereof extending outwardly through an opening in the room such as a, window. The casing is adapted to rest on the window sill l2 and is retained in place by a finger I4 engaging the sill l2. Screws l6 may be provided to extend from the lower portion of the unit to the wall to provideadjustable means for leveling the unit in place. 7 r r l The refrigeration system used in the unitcomprises a motor driven compressor IS, a condenser 20, a first evaporator 22 and a second evaporator 24. These components of therefrigeration system are connected'in refrigerant flow relationship as illustrated in Fig. 4 and are controlled 1 by apparatusto be described herein. They operate I ingthe dehumidification of air by recirculating a portion of the airback through the system so on the well-known multiple eflect refrigeration cycle which will be herein.

with means for creating a circulation of outside an inwardly over a portion of the condenser and outwardly through another portion of the condenser. This circulation of outside air through the condenser cools the condenser and dissipates heat therefrom. Fig. 1 illustrates the means by which this circulation of outside air is induced. The walls 26 and 28 illustrated in Fig. 1 form a compartment behind the condenser, a blower 86 is positioned in this compartment, a partition 32 divides the compartment and condenser. The blower 86 has an inlet opening positioned in operative relation with one portion of the condenser. The blower is adapted to discharge air to the other portion of the compartment and condenser unit defined by the partition 82. The inlet oriflce on the blower has been designated 24 and the discharge orifice has been designated 86. I

The air conditioning unit is adapted to circulate room air and to cool this circulated room air as it passes through the unit. Each side wall of the housing I6 is provided with an opening 88 through which air may be drawn from the room. Air entering the housing through the openings 88 is drawn through a pair of filters 46 to a plenum chamber 66. Th air is then drawn downwardly through the evaporator 24 and cooled.. The circulation of air is created by a blower 42.- The scroll 44 of the blower 42 has a discharge opening in the back of a drum 46. Suitable control means is associated with the drum 46 so that the air from blower 42 may be discharged into the room. This control means will be described herein.

In addition to the circulation of room air described above fresh air may be drawn from the outside of the building and mixed with the circulating room air. A partition 48 cooperates with a side wall of the housing to form a passage 56 which has one end thereof projecting through the window to the outside air. A filter 62 is positioned across the entrant portion of the passage 66. The evaporator 22 previously referred to is positioned in the passage 66 and a fan -54 driven by a suitable electric motor is adapted to force outside air through the evaporator 22 and into the plenum chamber 66. Control of the fan 64 and a damper 56 regulate the amount of air, if any, which is to be drawn through the passage 66 into the plenum chamber 56.

In addition means are provided for the optional admission of warmed fresh outside air into the plenum chamber 66. A damper 66 is associated with the partition 28 so that the air being drawn in through the condenser 26 by the blower drical in shape and provided with a pair of end bells 62 which are rotatably mounted on shafts 64. Each end wall of the drum 46 is provided with an opening 66 and the adjacent flat wall of the associated end bell 62 is provided with an opening 66.. The openings 66 and 66 are eccentrically positioned relative to the axis of the cylindrical drum and relative to the shaft 64. The

,66 ma have a portion thereof deflected into the 4 n! 66 when the end bell is suitably rotated by means of a knob 16. The outer surface of the end bell is provided with a segmental escape opening 12. A stack 14 is provided in the housinl l6. The opening I2 in the end bell is'sopositioned that it registers with the stack 14 when the opening 66 is registering with the opening 66.

Air may be by-passed from the drum 46 through the openings 66 and 66 into the end bell 62 from whence it may pass upwardly through the escape opening 12 and through the stack 14 into the plenum chamber 66 to be recirculated through the evaporator coil 24 for additional cooling. It has been found that treating a portion of the airadds very appreciably to the total effective cooling by increasing the ratio of dehumidiflcation on mild very humid days.

The drum 46 has a cylindrical contour and a hemicylindrical portion thereof projects outwardly beyond the front face of the casing II. The hemicylindrical portion of the drum 46 is provided with a plurality of directional vanes 16 which ar preferabl provided adjacent stamped slots in the surface of the drum. The vanes 16 are substantially radially arranged relative to the cylindrical drum 46. The vanes 16 cooperate with the associated ,slots 18 to direct air from the drum 46 into the room in desired directions. The drum 46 is preferably arranged on a horizontal axis. The vanes and slots preferably extend. longitudinally of the drum, but there is provided a centrally located peripheral portion which is uninterrupted by these slots or vanes. The central peripheral portion is provided with a'slot 86 which extends circumferentially about a portion of the drum. The slot 68 provides a means by which a pair of exteriorhandles 62 and 64 may connect. with a pair of dampers 86 and 66. The dampers 66 and 66 are arcuate and adapted to slide relative to the internal surface of the drum 46., The damper 86 is positioned in the upper portion of the drum 46 and adapted to control the discharge of 'air through the slots 18 in the upper segment of the drum. The damper 88 is adapted to control the discharge of air through the slots I8 in the lower segment of the drum. The dampers 66 and 68 may be brought into abutting relationship on a substantially horizontal lin thus preventing the discharge of air from the unit. By-selectively moving the damper 66 or the damper 68 the direction of discharge of air may be controlled by selecting which slots are to be exposed. By varying the number of slots exposed the velocity of the air being discharged may be varied.

The refrigerant apparatus discussed herein is provided with suitable means for the disposal of moisture which accumulates on the evaporator 24 as air is being cooled and dehumidifled by its heat exchange relation with the evaporator -24. The moisture which precipitates on the evaporator 24 drops by gravity and is collected by a series of collectors 66 which are so arranged that they do not impede the flow of air but do present surfaces to catch falling moisture. Each collector 66 is inclined rearwardly of the unit and is operatively associated with a trough 82. The trough 62 is drained by a tube 84 preferably having a U bend therein to provide a liquid seal between the compartments. The end of the tube 84 projects through the scroll housing of the blower 86 and is positioned above the rotor blades of the blower 36 so that the condensed moisture dropping from the tube 64 will be contacted by the rotor blades and opening 66 is adapted to register with the open- 15 beaten into aflne spray which facilitates evaporaair. The evaporated moisture maybe carried outside the 'buildingwith,

h wnflewr air. The bottom portion of the scroll of the blower I is provided "with a drain .0. A tube ll is'adapted to operatively connect the drain ll with the interior portion of the blower 8|. Moisture from the tube 04 which is not evaporated by the condenser cooling air will collect in the scroll housing of the blower 30. The differential in pressure between theinterior portion of the blower and the drain 08 will provide a means for lifting the moisture through tube 08 back into contact with the rotor blades. There is thus provided means for recirculating the moisture until it is evaporated.

An additional tube 02 is provided to dispose of any moisture which may collect on the floor 05 of that portion of the unit which projects through the wall of the building. This moisture could be derived from either spray escaping from the blower 30 or rain water being driven in through the condenser 20. The tube 82 is adapted to utilize the difierential in pressure between the interior of the blower rotor and the atmosphere to lift the moisture in the tube 93 into the interior of the blower in the same manner that the tube 08 operates.

Fig. 7 illustrates a schematic drawing of the various paths of air through the condenser unit. The path of room air through the evaporator 24 has been designated by the lines I00, IM and I02. The path of fresh outside air through the evaporator 22 has been designated by the lines I04 and I06. The line I06 merges with the line I00. The

.6 rater 22 operates at relatively high temperature.

Previous systems attempting to a am- Pr vided a relatively large evaporator, which alth cientdiifei'ential have u h itdoes pr vide therequired diiferentiali'or dehumidiiication; operates very inefliciently because the refrigerant volume is great. The suction line I20 of coil 22 is connected with the suction ports I20 of compressor Il. A suction line I30 of the evaporator I24 is connected with the suction valv 8 of the compressor I0. The admission of refrigerant to evaporator 22 is controlled by an expansion valve I22 operated by a diiferential pressure controlled valve I34 which is responsive to a heat sensitive bulb I20 connected to the discharge line I20. The admission of refrigerant to the evaporator 24 is through an expansion valve I40 operated by a diaphragm motor I42 controlled by a heat sensitive bulb I44 attached to the pipe I30 The suction line I28 from evaporator 22 containsrefrigerant still able to do some cooling recirculation of air through the evaporator 24 by means of the end bell 62 has been designated by dotted lines I08 and H0. The bleeding of warmed condenser cooling air through the damper 60 has been designated by the line H2.

. Referring to Fig. 4 the refrigeration system employed herein is illustrated. This system is of the type generally referred to as a mulfip-le efiect system. The compressor I8 is provided with a reciprocating piston II4, a discharge valve H6, a suction valve H8 and supplemental suction ports I20 which are positioned in the walls of the compressor cylinder at a location between the limits of piston travel. The discharge valve IIS of the compressor I8 is connected by pipe I22 with the condenser coil 20. A pipe I24 provides a fluid flow connection from the condenser 20 to the evaporator 24 for the passage of liquid refrig-' erant. A branch line I26 which is connected to the pipe I24 operatively connects the condenser "and the evaporator 22. An important feature of this invention resides in the fact that two separate evaporators operating at different temperatures and pressures from one compressor are provided in the room air conditioning unit. The outside air is usually at a higher temperature than the cooled room air. It is therefore possible to maintain a suflicient differential in temperature between the outside air and its associated evaporator 22 by having the evaporator 22 operate at a higher temperature than is possible with the evaporator 24. Thisincreases the efficiency by having the refrigerant operate at a higher temperature, pressure and density. The dehumidification of air being cooled requires that a sufllcient differential in temperature exist between the air and the evaporator. The differential has been found to be in the neighborhood of 30",. A vsuitable differential for the' dehumidification maybe obtainedeventhough the evapoand is preferably positioned in heat transfer relation with the liquid refrigerant entering evaporator 24 through line I24 so that a pre-cooling of the refrigerant for evaporator 24 is obtained. The heat transfer is preferably such that the directions of travel of the cold refrigerant in line I20 and the liquid refrigerant in line I24 are in opposite directions. This facilitates the precooling of the liouid refrigerant by assuring that the coldest portion of the line I28 (this is the portion containing refrigerant which has not yet passed in heat transfer relation with line I24) is positioned adjacent that portion of the line I24 containing liquid refrigerant which has been cooled. The pre-cooling is facilitated by the proximity between the coldest portions of each line rather than having the coldest portion of one line in contact with the hottest portion of the other line.

Experience has shown that the optimum benefit of the multiple effect system may be obtained with approximately a ito 1 ratio between the sizes of the evaporators. This experience is however based upon the humidity generally prevalent in the U. S. The proper ratio for any other climate may be computed.

In a unit drawing 270 C. F. M. over coil 24 and C. F. M. over coil 22 under certain conditions of outside and inside wet bulb t mpertiires an increase of as much as 110% intotal cooling effect over a conventional system may be achieved as v Wet Bulb Leaving Coll Tot illustrated in the following tabl Table 1 Out ide Wet Bulb Inside Wet Bulb-- Wet Bulb Leaving Coil 22 .4. Wet Bulb Leavi g Coil 24 Suction Temp. F BTU by Coil 22. B'lU by Coil 24.-..

al. BTU-Conventional. Increase Outside Wet Bulb...... Inside Wet Bulb BTU by Coll 22. BTU by 00112 the above, Table 1 the'advantage 1 tained at substantially t'l' Fahrenheit while Table 2 illustrates the advantage achieved when the outside wet bulb is at the figures given and the inside wet bulb is maintained at substantially 62 Fahrenheit.

I claim:

1. In an air conditioner adapted to air condition a space, a multiple effect refrigerating system comprising a compressor, a condenser and first and secondevaporators arranged in refrigerant flow relationship, means to maintain the refrigerant in said first evaporator at a higher temperature and pressure than the refrigerant in said second evaporator, means to receive fresh air from outside said space and to circulate said fresh air over said first evaporator, means to admit air from said space to said conditioner and mix said air from said space with the cooled fresh air, means to pass the resultant mixture over said second evaporator and eject the cooled mixture into the space, means for receiving air from outside said space and passing it in heat exchange relation withsaid condenser to cool said condenser and means for selectively admitting in controllable amounts to said space a portion of the air heated by the condenser.

2. In an air conditioner, first means to receive air from a space to be air conditioned and to circulate such air through said conditioner, second means to receive freshair from outside said space and to circulate said fresh air through said conditioner in controllable amounts, a refrigerationsystem of the multiple-effect type in said air conditioner, said system comprising a first evaporator adapted to cool said fresh air, a second evaporator adapted to cool the recirculated air from said space, means to maintain said first evaporator at a higher temperature than said second evaporator, said first and second means being arranged to mix said first mentioned air with the cooled fresh air and to pass the resulting mixture over said second evaporator and eject the cooled mixture into said space.

3. An air conditioner containing a first means to' cool air and deliver it to a space to be cooled, a second means associated with said conditioner and adapted to obtain the air to be cooled from a plurality of sources, the first of said sources being the space to be cooled and a second of said sources being outside of said space, a third means associated with said conditioner and adapted to cool air obtained from said second source and a fourth means associated with said conditioner and adapted to heat air obtained from said second source, said third means and said fourth means being adapted to respectively'pre-cool and preto cool air and deliver'it to a space to be cooled.

a second means associated with said conditioner and adapted to obtain the air to be cooled from a plurality of sources, the first of said sources being the space to be cooled and a second of said sources being outside of said space, a third means associated with said conditioner and adapted to cool air obtained from said second source and a fourth means associated with said conditioner and adapted to heat air obtained from said second source, said third means and said fourth means being adapted to respectively pre-cool and pre-heat air from said second source prior to its mixture with air from said first source and association of the mixture with said first means and means to control the amount of air from said third means and said fourth means that is to be mixed with air from said first source.

6, In an air conditioner adapted to cool air and discharge the cooled air to a space to be air conditioned, means to control the velocity and direction of discharge of said air to said space, said means comprising a. curved housing, means forming a plurality of slots in said housing, a vane projecting outwardly from said housmeans to selectively cover said slots whereby a variation in the number of slots covered by said third means varies the velocity of the air being discharged and the selection as to which slots are covered determines the direction of'discharge of said air.

7. In an air conditioner adapted to cool air and discharge the cooled air to a space to be air conditioned, means to control the velocity and direction of discharge of said air to said space, said means comprising a curved hemi-cylindrical housing, means forming a plurality of slots in the curved surface of said housing, blower means to discharge air from said housing through said slots, a pair of curved plates slidably mounted in said housing and adapted to cover and uncover said slots, one of said plates being adapted to be moved in a first direction so that one of its edges travels between the limits of a substantiall horizontal position and a remote position, the other of said plates being adapted to be moved in a second direction so that one of its edges travels between the limits of a substantially horizontal position and a remote position whereby the selective movement of said plates condenser to cool the condenser, means to collect condensate from the evaporator and discharge the condensate on to the blower rotor source and a fourth means associated with said conditioner and adapted to heat air obtained from said second source, said third means and said fourth means being adapted to respectively pre-cool and pre-heat air from said second source prior to its mixture with air from said first source andassociationofthemixturewithsaidiirst 'ltanddiscbargethecooledairtoaspaeetobemeans.

where-by the condensate will be broken up into a fine spray which will facilitate evaporation by the condenser cooling air, and a tube penetrating the bottom of said scrolland having an open end directed in close proximity with the interior of said rotor whereby a diifcrential in air pressure may be utilized to recirculate une vaporated moisture in said scroll into contact with said rotor.

9. In an air conditioner adapted to cool air 9 air conditioned, means to control the velocity and direction of discharge of said air to said space, said means comprising a curved hemicylindrical housing having its axis arranged in a substantially horizontal plane, means forming a plurality of horizontal slots in the curved surface of said housing, blower means to discharge air from said housing through said slots, a pair of curved plates slidably mounted in said housing and adapted to cover and uncover said slots, one of said plates being adapted to be moved upwardly to expose the slots in the upper portion of said housing, the other of said plates being adapted to be moved downwardly to expose the slots in the lower portion of said housing whereby the selective movement of said plates selects the segment of said housing from which air is discharged and thereby selects the vertical component of the direction ofair discharge and controls the velocity of air discharge.

10. In an air conditioner, first means to receive air from a space to be air conditioned and to circulate such air through said conditioner, second means to receive fresh air from outside said space and to circulate said fresh air through said conditioner in controllable amounts, a refrigeration system of the multiple-eifect type in said air conditioner, said system comprising a first evaporator adapted to cool said fresh air, a second evaporator adapted to cool the recirculated air from said space, means to maintain said first evaporator at a higher temperature than said second evaporator, said first and second means being arranged to mix said first mentioned air with the cooled fresh air and to pass the resulting mixture over said second evaporator and eject the cooled mixture into said space, and means for recirculating a portion of the cooled mixed air back for a second pass through said second evaporator.

ALWIN B. NEWTON.

REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 2,123,497 Buchanan July 12, 1938 2,127,990 Candor Aug. 23, 1938 2,130,089 Hull Sept. 13, 1938 2,146,796 Dasher Feb. 14, 1939 2,236,190 Wolfert Mar. 25, 1941 2,272,093 McCormack Feb. 3,- 1942 2,296,741 Sanders Sept. 22, 1942 

